[Not Applicable]
1. Field of the Invention
The present invention relates to a golf club. More specifically, the present invention relates to a golf club with a weighting member composed of multiple materials.
2. Description of the Related Art
Golf club designs are constantly evolving with the primary purpose to improve a golfer""s performance. While the improvements may address a number of areas, a designer strives to design a more forgiving golf club. Forgiveness in a golf club may be achieved by shifting the center-of-gravity of a golf club to a desirable location, and creating a larger moment of inertia.
It is difficult to increase forgiveness in a golf club head composed of a homogeneous or monolithic material, such as stainless steel, since there is a limit on the overall weight of a golf club acceptable to the typical golfer. To overcome this difficulty, designers have resorted to combining different materials (high density and low density) to achieve the desired center-of gravity and large moment of inertia. A very high-density material provides a designer with the greatest freedom in improving the performance of a golf club head since less volume is needed to achieve the proper weighting. The most economical, commercially available material with a very high density is tungsten, which has a density of 19.3 grams per cubic centimeter.
One challenge in using heterogeneous materials is the ability to join the materials together in a golf club head. Numerous techniques have been created by the golf industry to join heterogeneous materials in a golf club head. One example is the GREAT BIG BERTHA(copyright) TUNGSTEN-TITANIUM(trademark) irons, developed by the Callaway Golf Company of Carlsbad, Calif., which used a screw to attach a tungsten block to the rear and sole of a titanium iron. Another example is the GREAT BIG BERTHA(copyright) TUNGSTEN-INJECTED(trademark) HAWK EYE(copyright) irons, also developed by the Callaway Golf Company, which feature an internal cavity with tungsten pellets in a solder, as set forth in co-pending U.S. patent application Ser. No. 09/330,292, for an Internal Cavity Tungsten Titanium Iron, filed on Jun. 11, 1999. An example of a wood is the GREAT BIG BERTHA(copyright) HAWK EYE(copyright) drivers and fairway woods, also developed by the Callaway Golf Company, which use a tungsten screw in the sole of a titanium club head body. Other techniques use adhesives to join the materials, press fit the materials, braze the materials, or structurally hold one material piece within another material piece using undercuts or pockets.
For the most part, these techniques require a precisely machined weighting piece to fit within a precise location on a golf club head. The most economical method is to cast a golf club head body with a cavity for the weighting piece and attaching the weighting piece with a screw. However, casting tolerance are low, and require either machining of the cavity itself, or machining of the weighting piece to fit each cavity. The use of softer materials is undesirable since this creates difficulty in finishing the final product due to smearing of such soft materials during grinding of the golf club head.
Further, a co-casting process, where the weighting piece is incorporated in the mold prior to pouring the base metal, is very problematic depending on the materials since the weighting piece is relatively cold when the hot liquid base metal is cast around it causing thermal shock. Also, thermal expansion mismatch of materials is a problem with co-casting of heterogeneous materials. Other problems arise during re-shafting, where the golf club head is heated to remove the shaft. Such heating will result in low melting temperature materials (epoxies and solder) to flow, resulting in the possible movement of weighting pieces.
The present invention allows for a golf club head to be easily weighted without precisely machined weighting components. The present invention is able to accomplish this by using liquid phase sintering for incorporating a weighting member composed of a multi-component material into the golf club head.
The most general aspect of the present invention is a golf club head with a body and a weighting member. The body has a striking plate, a heel end, a toe end and a cavity. The weighting member is composed of a multi-component material and is disposed in the cavity of the body.
Another aspect of the present invention is a cavity back golf club head having a body and a weighting member. The body has a striking plate, a toe end, a heel end and a main rear cavity opposite the striking plate. A top wall, a bottom wall, a heel wall and a toe wall define the main rear cavity. The bottom wall has a second cavity with a predetermined configuration. The weighting member is disposed within the second cavity and occupies the entire cavity. The weighting member is composed of a multi-component material.
Yet another aspect is a method for manufacturing a golf club head. The method includes introducing a multi-component powder/pellet mixture into a cavity on a body of a golf club head, and heating the multi-component powder/pellet mixture to a predetermined temperature for liquid phase sintering of the multi-component powder/pellet mixture. The predetermined temperature is above the melting temperature of one component of the multi-component powder/pellet mixture.
The multi-component powder/pellet mixture may be composed of a heavy metal component, an anti-oxidizing component and a metal binder component. One variation of the multi-component powder/pellet mixture may be composed of tungsten, copper and an anti-oxidizing component. The anti-oxidizing component may be chromium or any chromium containing alloy such as nickel-chrome, stainless steel or nickel-chromium super alloy. Preferably, the anti-oxidizing component is nickel chrome.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.